A Hybrid Submodule Three-Phase Multiplexing Arm Modular Multilevel Converter With Wide Operation Range and DC-Fault Blocking Capability

Abstract

Three-phase multiplexing arm modular multilevel converter (TPMA-MMC) possesses lower cost, smaller volume, and higher efficiency compared with MMC. However, the limited operation range limits its popularity. Hence, in this article, it redefines the arm submodule (SM) configuration type, where the conventional arm is configured with full-bridge SMs (FBSMs), and the multiplexing arm is formed by half-bridge SMs (HBSMs). Meanwhile, a new energy balance principle and modulation scheme are proposed to expand TPMA-MMC’s operation range. Furthermore, the dc-fault blocking schemes could be implemented to realize dc-fault tolerance reliably without the multiplexing arm blocking. Compared with hybrid MMC(H-MMC), it could reduce by 33.33% in SMs a least, which leads to lower footprint and operation loss. Due to reregulating the energy flowing path of multiplexing arm and rearranging the chain-link voltage of multiplexing and conventional arm, it could reduce the required SM capacitance and further decrease the 65% energy storage requirement, resulting in improving the power density. Finally, the topology control scheme and dc-fault blocking scheme are verified by simulation and scale-down prototype experimental results.